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    <title>Document</title>
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    <script>
        var arr = [1,2,3,4,6,8]
        // arr.splice(2,2,'html','css')
        // console.log(arr)
        var res = arr.filter(item=>{
            return item>2
        })
        console.log(res)
        var str = 'feowih834gbfdhj'
        var res = str.indexOf('f',[5])
        var list = str.search(/H8/i)
        console.log(res)
        console.log(list)
        var match = str.match(/\d/g)
        console.log(match)
        var sub = str.substr(3,5)
        console.log(sub)
        var sli = str.slice(-3,-1)
        console.log(sli)
        var char = str.charCodeAt(3)
        console.log(char)
    </script>
</body>
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